It is known to use modular lighting systems to illuminate extended areas, such as within a display case or underneath a shelf or in a cove. Such prior modular lighting systems, which are sometimes referred to as linear lighting systems, typically include a number of elongated lighting fixtures which can be mounted to a surface or support structure, and which are electrically interconnected in an end-to-end fashion in a string or “daisy chain”, often in straight line segments. A power source is typically connected to a lighting fixture at the end of the string, which passes electrical power to all of the other lighting fixtures. A lighting installation having a length suitable for a particular situation can be achieved by combining a number of lighting fixtures in a string to create a lighting installation of an appropriate total length. An installation may include several spaced-apart illumination segments electrically connected together in a string, with each segment including several closely-spaced lighting fixtures, to create several separate areas of illumination, such as for a number adjacent display cases or shelves, or the like.
Each lighting fixture of such prior systems typically includes an illumination source designed to attempt to achieve a substantially even level of illumination over the length of the lighting fixture, such as an elongated fluorescent light source, or a number of individual light-emitting diode (LED) light sources spaced at intervals along a length of the lighting fixture. The lighting fixtures may include a light diffuser or other optical elements deigned to attempt to produce an even level of illumination along the length of the lighting fixture.
In prior art systems, the lighting fixtures are electrically interconnected using an axial inter-connector having two male portions extending outwardly in opposite directions from either side of a central separator portion of the inter-connector. Each male portion is received in a female recess in the end of an adjacent lighting fixture and is inserted therein in a direction in-line with or along the long axis of the lighting fixture. The central separator portion of the inter-connector is disposed between the adjacent lighting fixtures and requires that the lighting fixtures be separated from one another at least at a minimum spacing distance to accommodate the presence of the inter-connector between the lighting fixtures.
To assemble a string of such prior art lighting fixtures at the minimum spacing distance, a first lighting fixture is fixed to a support structure, for example within a display case. Then, an inter-connector is inserted axially into an end of the first lighting fixture. Then, a second lighting fixture is mated with the inter-connector, in the same, axial direction, with the central portion of the inter-connector located between and separating the first and second lighting fixtures. Once the second lighting fixture is mated with the inter-connector, the lighting fixture may be fixed to the support structure. To add a third lighting fixture, another inter-connector is inserted axially into the other end of the second lighting fixture. The third lighting fixture is mated to that inter-connector and then fixed to the support structure. As can be appreciated, instead of fixing the lighting fixture to the support structure one-by-one, as described above, the lighting fixtures and inter-connectors can be assembled prior to mounting, and then mounted together as a unit to the support structure. In any case, however, in order to remove and replace a lighting fixture located between two other lighting fixtures arranged at the minimum spacing distance, or to remove and replace any inter-connectors of such an arrangement, it is necessary to remove one or both of the adjacent lighting fixtures, and, in some cases, it is necessary to remove all of the lighting fixtures.
Illumination needs sometimes change after lighting systems are installed, and, while lighting systems are usually designed to last many years, lighting fixtures and inter-connectors sometime fail or require replacement. With the prior lighting systems it is difficult or impossible to replace a lighting fixture located between two adjacent lighting fixtures or to replace an inter-connector between lighting fixtures, when the lighting fixtures are mounted at the minimum spacing distance, without removing or damaging the lighting fixtures on either side, or, in some cases, without removing all of the other lighting fixtures. Installations of such lighting systems, especially in commercial environments, can include a large number of individual lighting fixtures (for example 20 or more) and can extend over a large distance (for example 20 to 100 ft or more). Therefore, the effort and cost of replacing individual lighting fixtures, or replacing or modifying inter-connectors, in such prior systems is significant and has been a deterrent to their adoption and use.
A goal of such lighting systems is to provide a substantially even level of illumination along the entire length of the entire installation (or at least along each illumination segment) to avoid significant or noticeable “dark spots” between lighting fixtures. A technique to avoid or minimize such dark spots between adjacent lighting fixtures is to mount adjacent lighting fixtures as close to one another as feasible. However, such prior art lighting systems can include dark spots between lighting fixtures because portions of the inter-connectors of the prior systems are located between adjacent lighting fixtures and require that the lighting fixtures be spaced apart from one another at an undesirably large spacing distance to accommodate the presence of the central portion of the inter-connector.
Therefore, what is desired is a modular lighting system having a number of individual, elongated lighting fixtures electrically inter-connectable in an end-to-end fashion where a lighting fixture within a string of lighting fixtures arranged at a minimum spacing distance, or an inter-connector between such lighting fixtures, can be removed and replaced, without damaging or removing any of the other lighting fixtures in the installation regardless of how many lighting fixtures are interconnected and regardless of the total length of the installation, to reduce the time and cost required to perform modifications and repairs of such lighting systems. Furthermore, what is desired is such a modular lighting system where adjacent lighting fixtures can be electrically interconnected without requiring that the lighting fixtures be spaced apart from one another, to avoid dark spots between adjacent lighting fixtures to provide an even level of illumination.